I'm not qualified to offer any direction on that coin/comm/charm, but I can say it is not Korean writing on it. One less country to search
Look like a novelty item for the newlywed. Obverse from top to bottom then right to left are ?合如意 which suppose be "prefect match and satisfied". Reverse are 百子千孙 which means hundred of sons and thousands of grandchildren. I do see a unfamiliar word in obverse and wrong writing pattern with ancient Chinese writing at the reverse. So I am assuming this is a modern creation from a poorly educated engraver.
Agree with TurboSnail after perusing my copy of David Hartill's Early Japanese coins. This example has a high probability of being Chinese. The Chinese characters (I am only good at more modern Japanese Kanji) imply "Hundred children and a thousand grandchildren". I do get the "satisfied or liking" character. The other characters I confess I do not know.